GB432210A - Sheet feeding mechanism for printing and like machines - Google Patents

Abstract

432,210. Printing-machines; feeding sheets. WAITE & SAVILLE, Ltd., Falcon Works, and WHYTE, F., 19, Queen's Terrace, both in Otley, Yorkshire. Dec. 21, 1933, No. 35913. [Class 100 (ii)] In a sheet-feeding device for printing or other machines of the kind in which the sheets are separated from a pile by suction separators 2, Fig. 1, and are finally fed by grippers 13 on oscillating arms 14, Fig. 5, to the grippers of an impression cylinder or the like, the action of the feeding devices is controlled by means of a pair of detector fingers 9 which are arranged over a feed plate 8 and adjacent to the front lays of the machine. From the pile 3 the sheets pass between rollers 4, 4a over a guide plate 4b, roller 5, and conveying tapes 6 to the plate 8. The fingers 9 are pivoted to arms 9a fixed to a shaft 11 which is normally oscillated at each feeding operation by means of a cam 28, spring- controlled lever 27, link 26a, and an arm 26 secured to the shaft 11. If, however, either of the detector fingers fails to be acted on by a correctly presented sheet, the finger remains in engagement with a notched bar 12, and the shaft 11 is not moved by the cam mechanism 28, 27 &c., and the normal operations of the gripper 13, the front lays, and sheet separator 2 are interrupted. These operations are normally effected by the shaft 11 in the following manner. The grippers 13 are normally operated by a cam 14<w>, Fig. 5, freely mounted on the shaft 15 of the oscillating arms 14 which carry the grippers. A projection 9<w> on the shaft 11 normally actuates a catch 31b and frees it from the path of a collar 32w on a camactuated rod 17 which actuates the cam 14w. When the shaft 11 is stationary the catch 31b prevents operation of the grippers. The front lays are normally depressed against the action of a spring 18c by an adjustable screw 19a carried by a lever 19 which is depressed by the arm 20b of a lever 20d oscillated by a cam 21 and spring 21a. A spring 19<d> communicates motion to the lever 19 by acting on a guide pin 19<c> secured to the lever. A weighted catch 23 tends to engage a projection 19f on the lever 19, but normally a rod 24 is actuated by an arm 10<a> on the shaft 11 and disengages the catch. When the shaft 11 is held fixed, the catch 23 holds the lever 19 and the front lays are not depressed. The air pressure in the pneumatic separator 2 is controlled by a valve 47c, Fig. 1, which tends to close under the action of a spring or gravity, and may be held open by a spring- pressed rod 45 controlled by a cam 43 contacting with a lever 44 connected to the rod 45. A spring 46 tends to move the rod 45 to permit the valve 47 to close but the raised part of cam 43 keeps the valve open. When the shaft 11 is held, a projection 26d on the rod 26a is kept out of the path of a projection 41f on a lever 41 which is thus permitted to move under the action of a spring 41a and cam 40 so as to cause the end 41b of the lever 41 to rotate the cam 43 clockwise and thus cause the valve 47c to remain open and so stop the feed. The roller 43 remains on the circular part of the cam and the feed remains stopped until the cam is returned by means of a handle 43<w> to its original position. A modified form of cam is shown in Fig. 6 provided with a longer cam surface 43b which prevents the roller 43a from passing on to the circular part of the cam. This prevents the necessity of having to return the cam by hand when the feed is stopped temporarily by reason of a slow rate of feeding and consequent failure of a sheet to reach the front lays at the correct time.